1. Field of the Invention
The present invention relates to an image recording apparatus, an image recording method, and a non-transitory computer-readable storage medium.
2. Description of the Related Art
Up to now, an image recording apparatus in which ink is ejected while a recording head having an ejection opening array constructed by arranging a plurality of ejection openings for ejecting ink is scanned with respect to a recording medium to record an image on the recording medium has been proposed.
In the above-described image recording apparatus, a recording system where an electrothermal transducing element is used, and thermal energy generated when a pulse is supplied to the electrothermal transducing element is utilized to eject the ink from the ejection openings has been proposed. According to the above-described recording system, even when the thermal energy is uniformly applied to the plurality of ejection openings in the ejection opening array, a temperature distribution of the ink in accordance with array positions of the ejection openings may be generated in some cases. Since the ejection amount of ink is increased as a temperature of the ink is higher, the ejection amount fluctuates among the ejection openings in accordance with this temperature distribution, and as a result, density unevenness may occur in the image to be recorded.
To suppress the above-described density unevenness, Japanese Patent Laid-Open No. 4-250057 discloses that a recording head including a plurality of temperature sensors arranged at mutually different positions in an array direction of the ejection openings and a temperature adjustment heater that performs a temperature adjustment by heating an area in the vicinity of the ejection opening (hereinafter, will be also referred to as sub heater) is used. In more detail, a recording head including two sub heaters that can be mutually independently driven which are arranged in the vicinity of one end part and the vicinity of the other end part is disclosed. Japanese Patent Laid-Open No. 4-250057 describes that, even in a case where a temperature difference of the ink between the vicinity of one end part and the vicinity of the other end part in the ejection opening array occurs in a recording mode for performing the recording by decreasing the number of ejection openings used for the recording, the temperature difference between the end parts can be eliminated by making power settings in accordance with the temperature difference in the respective sub heaters and independently driving the sub heaters while the above-described recording head is used.
However, with the recording head of recent years, it is found that, even in a recording mode in which all of the plurality of ejection openings in the ejection opening array are used, for example, a temperature distribution in which a temperature on a central side in the ejection opening array is higher than a temperature on an end part side may occur in some cases. In a case where the above-described temperature distribution occurs, density unevenness may occur in an area between an area recorded from the central side in the ejection opening array and an area recorded from the end part side in the ejection opening array on the recording medium.
It is conceivable that this temperature distribution is derived, for example, from a state where heat dissipation via a substrate more easily occurs in the end part in the ejection opening array and the temperature is more easily decreased than the central part. In recent years, to suppress a landing position deviation of the ink in the ejection from the end part in the ejection opening array, a technique has been proposed with which the ejection amount from the end part side in the ejection opening array is set to be lower than the ejection amount from the central side to perform the recording. In this case, the number of times to drive the electrothermal transducing element corresponding to the ejection opening located on the central side in the ejection opening array is increased, and the above-described temperature distribution may more notably occur.
According to the technology described in Japanese Patent Laid-Open No. 4-250057, since the sub heaters are provided only in both end parts in the ejection opening array, the temperature distribution is not eliminated in the above-described case where the temperature at the central part in the ejection opening array is higher than the temperature at both the end parts. In addition, since a configuration of an electric circuit or the like becomes complicated in the recording head that can independently drive the plurality of sub heaters as in Japanese Patent Laid-Open No. 4-250057, an increase in a size of the recording head and an increase in costs may occur.
In addition, as described in Japanese Patent Laid-Open No. 4-250057, it is found that, even in a case where driving of the sub heaters is controlled so as to eliminate the temperature distribution by calculating a temperature difference between a temperature detected from a temperature sensor arranged in the vicinity of the ejection opening used for the recording and a temperature detected from a temperature sensor arranged in the vicinity of the ejection opening that is not used for the recording, the following problem may occur. In a case where a use frequency of the ejection opening used for the recording is high, the temperature of the temperature sensor in its vicinity is increased, and the temperature difference from the temperature sensor arranged in the vicinity of the ejection opening that is not used for the recording is expanded, so that the power of the sub heater in the vicinity of the ejection opening that is not used for the recording is to be further increased. As a result, the detection temperature difference and the temperature distribution are to be eliminated, but the entire recording head accumulates heat, and the temperature is increased. Thus, it is found that a state of an excessive increase in the temperature is established, and an ejection performance may be decreased.